The function of the air flow sensor is to convert the amount of air drawn into the engine into an electrical signal and provide it to the electronic control unit (ECU), which is the main basis for determining the basic fuel injection volume.
Wing type air flow sensor:
The fin type air flow sensor belongs to the volume flow type. The sensor has a simple structure and low cost. However, because its moving parts fins occupy a large area of the intake duct, the fluidity of the intake system is reduced, and the intake resistance is increased. , So it is less used now.
Karmen vortex air flow sensor:
The Karman vortex air flow sensor belongs to the volume flow type and is widely used in Toyota and Mitsubishi. The sensor has the characteristics of small size, light weight, no wear, simple air intake, small air intake resistance, high detection accuracy, and quick response. However, the cost is relatively high, and it is mostly used in high-end cars.
Hot wire air flow sensor:
The hot-wire air flow sensor belongs to the mass flow type, which can directly detect the mass flow of the intake air without the need to correct the intake air temperature and atmospheric pressure. Because the sensor has no moving parts, the air intake resistance is small, and the response characteristic is good, and it can accurately detect the air intake volume during sudden deceleration, so it is widely used.
Hot film air flow sensor:
The hot film air flow sensor is a mass flow type, developed by General Motors of the United States, and is widely used in vehicles produced by General Motors and Isuzu Corporation of Japan. The working principle of the sensor is basically the same as that of the hot wire sensor, except that the hot wire of the heating element is changed to a hot film (consisting of heat-generating metal platinum fixed on a thin resin film). This structure can make the heating element not directly bear the resistance generated by the air flow, thereby increasing the strength and improving the reliability during work.
Post time: Dec-01-2021